The present invention relates to intermediate compounds useful in the synthesis of carbapenem antibiotics. The carbapenems derived from the present invention are useful against gram positive microorganisms, especially methicillin resistant Staphylococcus aureus (MRSA), methicillin resistant Staphylococcus epidermidis (MRSE), and methicillin resistant coagulase negative Staphylococci (MRCNS). There is an increasing need for carbapenems effective against such pathogens, as well as intermediates which facilitate their production. The intermediates of the present invention thus facilitate an important contribution to therapy for treating infections caused by these difficult to control pathogens.
Prior syntheses of similar intermediate compounds have relied on time-consuming, multi-step reaction protocols, and have generated the intermediate as an unstable oil. See, e.g., U.S. Pat. No. 4,960,879, Shionogi and Co. Ltd. The present invention responds to the need for a more facile synthesis yielding novel, more stable carbapenem intermediates.
The present invention relates to a process for preparation of a compound of formula I: 
wherein:
R1 represents CH3 or H; and P represents a protecting group;
comprising reacting a compound of formula IV: 
xe2x80x83wherein R1 and P and are defined above and R4 represents triflate or SO2F;
in the presence of a catalyst and (R3)3SnCH2OPxe2x80x3, wherein: each R3 represents C1-4 lower alkyl, and Pxe2x80x3 represents H or a protecting group, to yield the compound of formula I.
This one-vessel process is a more efficient and facile pathway than the traditional multi-step synthesis for preparation of carbapenem intermediates.
The present invention also relates to the compound of formula I: 
wherein:
R1 represents CH3 or H; and P and Pxe2x80x2 independently represent H or a protecting group. This novel compound is a stable and storable crystalline solid.